This document relates to communicating messages between systems.
In some cellular telephone networks, push-to-talk (PTT) services have been deployed. One approach to such communication makes use of the PTT over Cellular (PoC) standard, which is defined by the Open Mobile Alliance (OMA) and the 3GPP/3GPP2 IMS standards bodies. PTT generally provides a walkie-talkie like service allowing ad-hoc chat voice communications. In general, a PoC system makes use of servers within a telephone system's data network that maintain and exchange presence information of client telephones registered with those servers. The servers also participate in exchanging of messages containing bursts of recorded voice messages.
In data network domains, such as on the public Internet, Instant Messaging (IM) system have been developed and deployed enabling users register with such systems to send text messages to one another. Examples of such systems have been deployed by AOL, Yahoo, Jabber, and others, which enable users to exchange messages over the Internet. Enterprise-based messaging systems have also been developed, including the Microsoft Live Communication Server. In general, IM services enable users to create a kind of private chat room with another individual in order to communicate in real time, for example, over the Internet. Some text systems have been extended to allow recorded voice messages to be exchanged between users of the systems. In general, IM systems make use of one or more centralized servers that maintain presence information related to the users, and that route messages between the users.
Some IM clients, such as from Trillian by Cerulean Studios, can communicate with a number of different IM networks (but not the cellular PTT network), and aggregate presence and contact information in a client which communicates with all network types.
Some IM and PoC networks have separately migrated to use of to the Session Initiation Protocol (SIP) as a base protocol. However existing PoC and IM networks utilize different procedures and presence models, operate on decoupled data networks, and have not been integrated to form an interoperable system.